The present invention relates to locomotives, and more particularly to a method that safely increases a locomotive's acceleration rate when the locomotive is increasing to full horsepower.
Depending on a geographic region, locomotives used for passenger applications make more frequent stops for shorter periods of time when compared to locomotives used for freight applications. Freight trains usually travel from one city to another, where the cities are several hundred miles apart. Freight trains generally do not make periodic stops between a starting and final destination. Thus starting a freight locomotive may take considerable time, such as over a minute, to accelerate to full horsepower and/or to a desired horsepower. Even though there are passenger trains that also travel between cities separated by hundreds of miles, many passenger trains are also used within a city wherein they make scheduled stops a few blocks, such as two miles, apart at stations where passengers embark and debark the train. Each time a passenger train departs from a station, it typically takes between 40 to 60 seconds to accelerate to full horsepower, due to engine loading limitations or engine load rates.
Freight trains and passenger trains use the same railroad tracks. To avoid accidents, such as having a freight train overtake a passenger train stopped at a station or while slowly accelerating after leaving a station, trains are scheduled to allow for a given amount of time, such as 2 minute intervals, between them. With respect to the stops made by passenger trains, scheduling the use of a track must include considering the time a passenger train must spend at each station as well as the time it takes for the passenger train to accelerate from a stopped position to a normal traveling speed. Otherwise, train schedules can be thrown off and train intervals greatly affected.
Currently train schedules for railroad tracks in which both passenger locomotives and freight locomotives use are limited by the time passenger locomotives need to stop and then start again, including the time it takes for them to reach full horsepower after leaving a station. If a passenger train could accelerate faster when leaving a station, not only does the chance of slowing down other trains lessen, but schedules can be revised where more trains could use the track over a given time period.